Horton

Re: upgrades in row-level locks can deadlock

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Oleksii Kliukin <alexk@hintbits.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-06-13T21:37:31Z
Lists: pgsql-hackers 
On 2019-Jun-13, Alvaro Herrera wrote:

> On 2019-Jun-13, Oleksii Kliukin wrote:
> 
> > Makes sense. For the symmetry I have included those that perform lock
> > upgrades in one session and those that doesn’t, while the other sessions
> > acquire locks, do updates or deletes. For those that don’t upgrade locks the
> > test checks that the locks are acquired in the correct order.
> 
> Thanks for the updated patch!  I'm about to push to branches 9.6-master.
> It applies semi-cleanly (only pgindent-maturity whitespace conflicts).

Done, thanks for the report and patch!

I tried hard to find a scenario that this patch breaks, but couldn't
find anything.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Avoid spurious deadlocks when upgrading a tuple lock